The disclosure of Japanese Patent Application No. 2001-012468 filed on Jan. 19, 2001 and No. 2001-227348 filed Jul. 27, 2001, including the specification, drawings and abstract, is incorporated herein by reference in its entirety.
1. Field of Invention
The present invention relates to systems and methods for controlling a vehicle-occupant protecting apparatus such that an appropriate vehicle-occupant protecting devices of the vehicle-occupant protecting apparatus is operated upon detection of a crash or a rollover motion of an automotive vehicle.
2. Description of Related Art
A control system for controlling a vehicle-occupant protecting apparatus of an automotive vehicle is well known, which includes vehicle-occupant protecting devices such as airbags and seat-belt pre-tensioners. The control system is arranged to determine whether the vehicle has a rollover motion, on the basis of roll angle and rate of the vehicle, and to operate the appropriate vehicle-occupant protecting device or devices when the rollover motion of the vehicle is detected. In this respect, it is noted that the vehicle occupants (in particular, the upper part of their bodies) are moved toward the right or left side of the vehicle body during turning of the vehicle. Accordingly, the rollover motion of the vehicle which takes place during turning of the vehicle causes a reduction of a space which is provided adjacent to an airbag disposed on the right or left side of the vehicle body, and which would accommodate the airbag that has been inflated due to the rollover motion of the vehicle.
In view of this drawback, JP-A-2000-9599 discloses a control system which is arranged to effect a determination as to whether the vehicle is turning, on the basis of the detected steering angle of the vehicle. Moreover, the control system effects a determination as to whether the vehicle has a rollover motion, on the basis of the detected roll angle and rate of the vehicle while the vehicle is not turning, and on the basis of a detected lateral acceleration value of the vehicle as well as the detected roll angle and rate, while the vehicle is turning. This arrangement permits a relatively early detection of the rollover motion of the vehicle during turning of the vehicle.
The rollover motions of the vehicle in JP-A-2000-9599 include a xe2x80x9ctrip-overxe2x80x9d motion which takes place due to a collision of the vehicle wheel or wheels with stationary objects, such as edge blocks arranged along an edge of a roadway, and a xe2x80x9cturn-overxe2x80x9d motion which takes place during abrupt turning of the vehicle. A determination as to whether the vehicle has such a trip-over or turn-over motion is advantageously effected on the basis of the lateral acceleration value and the roll rate of the vehicle, since an increase of the lateral acceleration value occurs at an earlier point of time than an increase of the roll rate. However, this arrangement may cause an erroneous determination that the vehicle has a rollover motion, in the event of crashing (a side crash, in particular) of the vehicle, while in fact the vehicle does not have a rollover motion. This leads to a risk of an unnecessary operation of the vehicle-occupant protecting device or devices of the vehicle-occupant protecting apparatus.
The present invention was made in view of the drawbacks discussed above. It is therefore an object of the present invention to provide control systems and methods for a vehicle-occupant protecting apparatus, which permits accurate determination as to whether the vehicle has had a rollover motion, and which prevents an unnecessary operation of the vehicle-occupant protecting apparatus.
According to one aspect of the present invention, there is provided a control system for controlling a vehicle-occupant protecting apparatus provided on an vehicle such that the apparatus is controlled upon determination that the vehicle has a rollover motion, the control system comprising: a first detector that determines whether the vehicle has crashed; a second detector that determines whether the vehicle has a rollover motion; an invalidating device that invalidates the determination by the second detector that the vehicle has the rollover motion, such that the determination by the second detector is invalidated for a predetermined time after the determination is made by the first detector that the vehicle has crashed; and a controller that controls the vehicle-occupant protecting apparatus based on outputs of the second detector and the invalidating device. The invalidation by the invalidating device of the determination of the rollover motion may be effected by either invalidating the determination which has been made by the second detector, or preventing the second detector from making the determination per se.
According to another aspect of the present invention, there is provided a method of controlling a vehicle-occupant protecting apparatus provided on an vehicle such that the apparatus is controlled upon a determination that the vehicle has had a rollover motion, comprising the steps of; determining whether the vehicle has crashed: determining whether the vehicle has had the rollover motion; invalidating the determination that the vehicle has had the rollover motion, such that the determination is invalidated for a predetermined time after the determination is made that the vehicle has crashed; and operating the vehicle-occupant protecting apparatus based on the determination whether the vehicle has had the rollover motion and the invalidation of the determination that the vehicle has had the rollover motion.
The control system and method of the present invention described above are arranged such that the determination that the vehicle has had a rollover motion is invalidated upon determination that the vehicle has crashed or collided (a side crash, a front crash, a rear crash, etc.), for a predetermined time after the determination has been made that the vehicle has crashed. Accordingly, at least one vehicle-occupant protecting device of the vehicle-occupant protecting apparatus, which would be operated upon an actual rollover motion of the vehicle, is not actually operated for the predetermined time after the determination has been made that the vehicle has crashed, if an erroneous determination that the vehicle has had a rollover motion is made where the rollover motion has not actually taken place upon the crashing of the vehicle. Thus, the present control system and method prevent unnecessary operation of the vehicle-occupant protecting device or devices.